Understanding whether the risk of developing Alzheimer's disease (AD) is changing over time is critical for accurately estimating the future public health impact of the disease, especially resources needed to care for people with AD. All projections to date have assumed that the risk of developing the disease is constant over time. It is also important to assess the degree to which any observed changes in risk of AD over time exceed trends attributable to changing demographic and risk factor patterns. Previous information is limited as the two studies that most directly addressed the issue ended observation in 1972 and 1985, respectively, relied heavily on retrospective informant information and clinical records, and were not specifically designed to identify all cases of disease near the time of onset. The purpose of the proposed work is to provide a rigorous examination of the issue using recent data, and excellent methods. We propose to evaluate changes in levels of cognitive function and the risk of incident AD at specific ages in a single community observed with the same methods for 14 years. The proposed work can be accomplished at a reasonable cost using data from an existing large biracial population study. The Chicago Health and Aging Project requested participation of all persons age 65 or older in a geographically defined community beginning in 1994 and has continued observation of these individuals as well as enrolling additional people in the community who subsequently turned 65. Stratified random samples of the population receive standardized detailed clinical evaluation for diagnosis of AD. A total of 9,532 people have participated in the study, 1,428 people have been examined for the diagnosis of AD, and 287 individuals had probable AD. The questions to be addressed include the following: Has the age, gender and race specific level of cognitive function or the risk of developing AD, or the risk of mortality due to AD changed in recent years? Do changes in education, occupation, income or use of agents that may influence onset of AD explain changes? What are the implications of the findings above for rates of AD incidence in the US population? Relevance: The proposed study will use the best available data to determine whether the risk of developing Alzheimer's disease is changing over time and investigate factors that may account for the differences. This information is essential for planning the future health resources needed to care for people with AD. Principal Investigator/Program Director (Last, First, Middle): Hebert, Liesi E. The proposed study will use the best available data to determine whether the risk of developing Alzheimer's disease is changing over time and investigate factors that may account for the difference. This information is essential for planning the future health resources needed to care for people with AD. PHS 398/2590 (Rev. 09/04, Reissued 4/2006) [unreadable] [unreadable] [unreadable] [unreadable]